The present invention relates generally to surgical instruments and more specifically to surgical clip appliers used for applying ligating clips to blood vessels and other tubular ducts or tissue.
In surgical procedures, it is frequently necessary to ligate ducts, such as blood vessels, or other severed tissue. For this purpose, it is well-known to use surgical clip appliers, such as that described in U.S. Pat. No. 3,439,522, to apply surgical clips to a duct or tissue to be ligated. Such clip appliers typically have a scissor-like construction, with a pair of movable handles which are grasped by the surgeon, and a pair of movable jaws opposite the handles into which a surgical clip is placed. Such clips usually have a pair of connected legs to form a U or V shape. When the handles are closed, the jaws close the legs of the clip together on the vessel or other tissue to be ligated.
In some surgical procedures, it is desirable to use a clip applier which is configured to allow tissue ligation in inaccessible areas of the surgical site. To address this need, a number of surgical clip appliers have been developed with the jaws extended from the handles at a distance, or with the jaws oriented at various angles. Examples are described in U.S. Pat. Nos. 3,777,538, and 4,440,170.
Other known clip appliers, such as that described in U.S. Pat. No. 4,616,650, provide for retaining multiple clips in the applier and feeding the clips toward the distal end of the applier, thereby permitting the surgeon to apply multiple clips at various places in the surgical site without removing the clip applier from the site to place another clip in the jaws. In some of these known devices, the clip applier is designed to accommodate an interchangeable cartridge containing multiple clips. An example is seen in U.S. Pat. No. 3,675,688.
In some surgical procedures, however, known clip appliers suffer certain drawbacks. Known clip appliers pose a potentially serious risk of injury to patients in the event the jaws are closed when a clip is not present in the jaws. This may occur if the feeding mechanism is jammed, or if there are no clips remaining in the device. In such a case, known clip appliers generally do not prevent the user from attempting to apply a clip by positioning the jaws over a portion of tissue and closing the jaws on the tissue. The problem is worsened by the often poor visibility in the body cavity preventing clear visualization of the jaws and the presence of a clip therein. When the jaws are closed without a clip present, known clip appliers permit the jaws to move into contacting or overlapping engagement with one another, which in many cases will cut, sever or otherwise damage any tissue lying between the jaws.
For these reasons, it would be desirable to provide improved apparatus for applying surgical clips which eliminate the risk of tissue damage when a clip is not present in the jaws during closure. Preferably, the apparatus will provide complete closure of surgical clips for secure application to tissue, while at the same time providing a gap between the jaws in the closed position if a clip is not present therein so as to avoid tissue damage. The apparatus should be adaptable to various types of clip appliers, including those having a pair of movable jaws, as well as those having a stationary anvil and movable hammer, whether oriented in the distal or lateral direction.